I found this article on their site:
It’s very brief, but since that date they are saying that you can’t use 3D Warehouse directly with their program. They say to update to a particular version instead. I tried the current version, and it seems to be able to import SKP files up to version 2019. You would find what you need using your web browser, then download a 2019 format version of the model, and that should import into 2020 Design Live ok.